Mental Addition and Subtraction Tips - Math Tricks with Arthur Benjamin 

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I have more ways then he taught here .

you are a legendary grandpa

@@nelsonfung7642 really

@@nelsonfung7642 make a video then

@@Liana_2.0 yes I am about 6x of speed then others .

I strongly agree with you. The fundamentals of mathematics should be enjoyable .

Thank you for the feedback! We're happy to be part of your kid's learning path and appreciate the nice comments!

I did for many years.... told my students dont listen to school all the time

so true

Where are you from brother

Same

took you 2 seconds ? slow took me 1 second

That works but treating it as 766+500-11 is less steps so that might potentially be faster if you can recognize immediately that 489 is 11 away from 500.

I did 489+766 = (500-11)+766 = 500+(766-11) = 500+755 = 1200+55 = 1255 I've found it to be the most efficient way by far

Samebut i searched how to be a human calculator

@@XM.7 ,😯😄

@@CuteGirl-ok5rt ok since you are a cute girl, I recalled and researched. It is Math Magic, by Scott Flansburg

@@SuccessforLifester I know this man, it is the human calculator the most quickly man in the world !

@@barbeblanche1581 🙂. I don't know why cute girl message disappeared

Hi! Please check this link: www.thegreatcoursesplus.com/the-secrets-of-mental-math?v=Q2D8pp9lzgQ&lc=Ugz6FDuwP8VwDJHwdhZ4AaABAg If you are not a member, we encourage you to subscribe to get access to all the lectures! :)

Did you get better at mental math now?

Drill single digits. Sounds simple and wasteful, it is not. You want to know them instantly by recall. Then do it while being distracted by other things until you *know* them. You will know when you are going to have to "carry". When I think 766 + 489, I know 7+5 =12 (to be clear, 6 + 8 is going to result in a "carry"). So I would have 1246 + x as the person telling me the problem is saying the "ty" in eighty. Then when told 9, I would have the entire answer of 1255. When you *know* the single digits by heart, and being distracted, you can calculate the answer as you are being given the problem. No need to remember any numbers already given and can respond with the answer "instantly", even though you have the last number or two to finish completing the calculation. Having the answer a fraction of a second when they are done also allows you to continue the process if they continue with something else to be added. Again, you can discard what is already used. There are times I know the answer, and do not know what the problem was. Being distracted and able to still know allows you to do it while being told more (ie distracted), and use when they say "thousand", "hundred" "ty" to continue building the answer. If looking at a written question, looking at the next digit tells if a "carry" is needed. People under estimate needing to know the single digit, "quick and easy" calculations. That is all that is being done along each step, know them, and you know the answer without doing much other than changing digits to another digit you know they become. Practice using 2 digit numbers. Then you will start learning 2 digits + 2 digits is whatever. Ex. 15 + 35 = 50 (easy for most to instantly recognize), 65+ 26 = 91 (not so obvious for most) and so on. Then when good at 2 digits + 2 digits, move on to 3 digits. Use 1 digit at a time if the problem is verbal, if written use 1, 2 , or 3 digits if you know the larger grouping or not.

For the 66 and 89 with ugly numbers I always try to make them look friendlier. My go to steps to solve this would be: 1. take 66+89 and rewrite it as 86+89-20. 2. 80+80 is 160, then subtract 20 for 140. 3. For the 9+6. Make the 9 a 10, then you have 10+6-1. 10+6 is 16, 16-1 is 15 It looks complex and slow but it’s not very hard. The other solution is to just memorize numbers + numbers, and my teachers since 2nd grade criticized me for this method, but it has always been what came easiest to me. Another example is 7+6. 7+7 is 14, 14-1 is 13. It’s just an automatic thought process to me I don’t really think about it. Break down numbers to easier things to do mentally, you will have an easier time. Looking back on it, the other way I would solve it would be to make 66+89 66+90. From there it then becomes 90+10 for 100, then add 50 for 150. Then add 6-1 because you added 1 earlier . Both ways would be my response it’s a tossup for this. Hope this helps!

yes I do have more ways . you want to learn ?

Lovely people said lovely things